In addition, there has been a new article posted on the Windows Phone developer blog. Brandon Watson explains why the unofficial tool may have a negative impact on Windows Phones by putting them in a changed state, as opposed to an updated state (if looking at the devices as state machines).

When we test our update process, we test against a known state machine. Further, as a health protection mechanism, the phone will always try to recover from an error state (as in an incomplete update), and will begin doing things to solve for the fact that it is in an unknown state. This is the reason why phones started downloading OEM updates after forcing the update via this unofficial tool. It’s also the reason why people who used the unofficial tool to get to 7390 reported that their phones later updated to 7390 via the Zune PC software. The state machine looked more like pre-7390 than it did 7390. However, because of the existence of some of the 7390 bits on the phone, and the fact that the 7390 update process was not intended to run against this a priori unknown state machine, the result was an incomplete 7390 update.

If you have a phone that was updated using this unofficial tool, and you attempt to update to 7392 from the Zune software, you will get the error code 80180048. Zune is the only official way to update the operating system on the phones.

So, good news for you guys who are experiencing the 80180048 error when attempting to receive the May security update. It should be noted that the Chevron team are working on this fix and are taking responsibility off their own backs, which deserves much appraisal. The Windows Phone team are busy working on Mango among other workings which the unsupported tool is not apart of.

'Walsh Fix' Being Approved by Microsoft, Brandon Explains the Problem

Not all phones are created equal it seems. Some don't have any problems, some (samsungs) keep having problems. There have been a enough people posting with that update error though that a fix needed to be made. I find it kinda funny how some being able to update past 7390 means everything MS is saying must be BS yet now we have a new update and people are having problems. This should put that idea to rest now.